Source : Free On-Line Dictionary of Computing

greatest lower bound
     
         (glb, meet, infimum) The greatest lower bound of two
        elements, a and b is an element c such that c <= a and c <= b
        and if there is any other lower bound c' then c' <= c.
     
        The greatest lower bound of a set S is the greatest element b
        such that for all s in S, b <= s.  The glb of mutually
        comparable elements is their minimum but in the presence of
        incomparable elements, if the glb exists, it will be some
        other element less than all of them.
     
        glb is the dual to {least upper bound}.
     
        (In {LaTeX} "<=" is written as {\sqsubseteq}, the glb of two
        elements a and b is written as a {\sqcap} b and the glb of set
        S as \bigsqcap S).
     
        (1995-02-03)